Method for transmitting local area/wide area messages and selective call receiver for use therewith

ABSTRACT

A selective call receiver (102) for use in a communication system (100) includes a receiver (404), a memory (412), and a processor (408). The receiver (404) is capable of receiving a message code (314) during a first frame from a first transmitter and the same message code (314) during a second frame from a second transmitter. The memory (412) stores a first and a second canned message, wherein the first canned message corresponds to the message code (314) being received in the first frame and the second canned message corresponds to the same message code (314) being received in the second frame. The processor (408) is responsive to the message code (314) for identifying the first canned message in the memory (412) corresponding to the message code (314) and the first frame, and identifying the second canned message in memory (412) corresponding to the same message code (314) and the second frame.

This is a divisional of application Ser. No. 08/606,950, filed Feb. 26,1996 now U.S. Pat. No. 5,740,541.

FIELD OF THE INVENTION

This invention relates in general to RF (Radio Frequency) networks, andparticularly to such networks that communicate with selective callreceivers.

BACKGROUND OF THE INVENTION

Conventional wireless local area networks can be located within awireless wide area network, with both types of networks operating on asingle RF channel. A complex communication architecture is required tocoordinate communication between the local area networks and the widearea network. In one such architecture, a synchronization link isutilized to coordinate a master-slave relationship between the wide areanetwork and local area networks.

In a master-slave architecture, the wide area network is considered themaster while the local area networks are the slaves. As the master, thewide area network takes priority for communicating with selective callreceivers for which it has messages. Thus, when traffic density is high,the synchronization link gives the wide area network communicationpriority over the local area networks.

In order to prevent a lockout of the local area networks, thesynchronization link restricts the wide area network from communicatingwith the selective call receivers beyond a predetermined time period.Once the predetermined time period has been exceeded, thesynchronization link transfers communication priority to the local areanetworks.

Although this architecture is sometimes effective in delivering messagesto selective call receivers, during times of high traffic densities itcan prevent local area transmitters from delivering messages promptly toselective call receivers in their respective coverage areas. Thissituation can result in message latencies for local area networks thatare inconsistent with customer expectations.

Thus, what is needed is a method and apparatus that provides promptdelivery of messages by wireless local area networks located within awireless wide area network, with both networks operating on the same RFchannel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an electrical block diagram of a communication system thatoperates according to the present invention;

FIG. 2 is an electrical block diagram of the high power transmittershown in FIG. 1;

FIG. 3 is a timing diagram depicting the communication protocol used bythe communication system of FIG. 1;

FIG. 4 is an electrical block diagram of a selective call receiveraccording to the present invention;

FIG. 5 is a diagram depicting frame assignments in a non-frame reusecommunication system operating according to the present invention;

FIG. 6 is a diagram depicting frame assignments in a combined framereuse and non-frame reuse communication system operating according tothe present invention;

FIG. 7 is a diagram depicting the arrangement of canned messages in theselective call receiver of FIG. 4;

FIG. 8 is a flow chart showing how the high power transmitter operatesaccording to the present invention;

FIG. 9 is a flow chart showing how the low power transmitter operatesaccording to the present invention; and

FIG. 10 is a flow chart showing how the selective call receiver operatesaccording to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is an electrical block diagram of a communication system 100 thatoperates according to the present invention. The illustratedcommunication system includes a relatively high power transmitter 104for transmitting, on a given frequency, messages to selective callreceivers 102 located within a relative wide coverage area 114. Inaddition, the communication system 100 includes a plurality ofrelatively low power transmitters 108 for transmitting, on the samegiven frequency, messages to selective call receivers 102 located withina plurality of relatively smaller coverage areas 112 that each overlapthe relatively wide coverage area 114.

The high power transmitter 104 is coupled to a conventional transmitterantenna 106 for transmitting selective call messages to selective callreceivers 102 located anywhere within the wide coverage area 114,including receivers 102 that are located within the smaller coverageareas 112. Radio frequency (RF) signals are transmitted by the highpower transmitter 104 utilizing conventional means such as, for example,frequency shift-keyed (FSK) signals for transmitting digitized messages.

Similarly, each low power transmitter 108 is coupled to a conventionaltransmitter antenna 110 for transmitting information, including messagecodes and/or conventional messages, to selective call receivers 102located within its own small coverage area 112. RF signals aretransmitted by the low power transmitter 108 utilizing the samemodulation scheme utilized by the high power transmitter. In contrast tothe high power transmitter 104, the low power transmitter 108 has alimited transmission range for RF signals that can be intercepted by theselective call receivers 102. This range is essentially limited to theboundary of the small coverage area 112 shown in FIG. 1.

In operation, an individual receiver 102 may remain within a singlegiven small coverage area 112, in which case it will be able to receivetransmissions from the high power transmitter 104 and from the low powertransmitter 108 that is located in the same given small coverage area112.

Alternately, one or more of the receivers 102 may be expected to roamthroughout the wide coverage area 114. In this case, the roamingreceiver 102 could pass through all the smaller coverage areas 112 andthrough portions of the wide coverage area 114 that are not within oneof the small coverage areas 112. Such a receiver will, as describedlater, be able to receive transmissions from the high power transmitter104, as well as from each low power transmitter 108 that it comes withinrange of.

FIG. 2 is an electrical block diagram of the high power transmitter 104.The block diagram includes an input interface 208, a controller 206, atime base 212, a time base antenna 214, and a transmitter 202.

The input interface 208 is coupled to a conventional wire communicationlink 210 such as, for example, a conventional telephone line coupled toa public switch telephone network (PSTN) for receiving messagesoriginated by callers using a conventional telephone unit. It will beappreciated that, alternatively, the wire communication link 210 can bereplaced with a conventional wireless communication link such as, forexample, a microwave communication link.

The controller 206 is a conventional computer system used forcontrolling the operation of the high power transmitter 104. Thecontroller 206 is coupled to the input interface 208 for receiving voiceor data messages originated by a caller. The messages are processed bythe controller 206 in accordance with a communication protocol utilizedby the communication system (to be described below). The processedmessages become selective call messages intended for transmission to oneor more selective call receivers 102 located within the wide coveragearea 114.

The time base 212 receives synchronization signals from a common timebase such as, for example, a global positioning satellite (GPS). Thesynchronization signals are intercepted by the time base antenna 214utilizing conventional means well known in the art. The time base 212uses these signals to synchronize itself to the communication protocol.

The controller 206 is coupled to the time base 212 in order to processthe selective call messages in a manner that synchronizes them to thecommunication protocol. The synchronized selective call messages aredelivered by the controller 206 to the transmitter 202, which thenmodulates them for transmission to the selective call receivers 102 viaantenna 106. The transmitter 202 transmits the selective call messagesat an RF power level sufficient for the RF signals transmitted to beintercepted by selective call receivers 102 located anywhere within thewide coverage area 114, including those located within any one of thesmall coverage areas 112.

The low power transmitters 108 use substantially the same elementsdescribed in FIG. 2, with a few exceptions. An input interface like 208is used by the low power transmitter 108 for receiving information,preferably in the form of message codes, for transmission to selectivecall receivers. A message code is a short digitized code (e.g., 8 bits)transmitted to one or more selective call receivers 102 for recalling aselected canned message from the memory of the intended selective callreceiver 102 and presenting canned message to user(s) of the selectivecall receiver(s) 102.

It will be appreciated that, in addition to message codes, the low powertransmitter 108 can receive message information from the input interface208. This message information is transmitted along with the message codeto the selective call receivers 102 located in the small coverage area112. The message information comprises, for example, alpha-numericmessages or voice messages.

The input interface in a low power transmitter receives message codesfrom, for example, a local area controller (not shown) coupled to thelow power transmitters 108 by way of conventional wire communicationlinks, such as links 210. Alternatively, the low power transmitters 108may be preprogrammed with the message codes, thereby eliminating theneed for an input interface and a wire communication link in the lowpower transmitter 108.

The message codes are selectively transmitted by the low powertransmitters 108 to the selective call receivers 102 by modulating themessage codes at an RF power level sufficient for the generated RFsignals to be intercepted by selective call receivers 102 located withina small coverage area 112. Selective call receivers 102 located outsidethe small coverage area 112 are not able to intercept the transmittedmessage codes.

There are several important similarities between the high powertransmitter 104 and the low power transmitters 108. First, both types oftransmitters use the same communication protocol. Second, the time bases212 of each transmitter receives synchronization signals from the samecommon time base, i.e., the GPS time base. This allows the high powertransmitter 104, and the plurality of low power transmitters 108 tosynchronously transmit messages on the same communication protocolwithout interfering with each other.

FIG. 3 is a timing diagram depicting the communication protocol 300 thatis preferably used by the communication system 100. This protocol,developed by Motorola, Inc., is known as the FLEX digital selective callsignaling protocol (Flex is a trademark of Motorola, Inc.) that ispresently used by various system operators in the United States and inseveral other countries. More details of the Flex protocol can be foundin U.S. Pat. No. 5,371,737, assigned to Motorola, Inc. It will beappreciated that other communication protocols that operate in asynchronous communication system and that are suitable to this inventioncan be used. However, in the discussion below it is assumed that theFlex protocol is used.

The communication protocol 300 comprises a plurality of synchronousframes 302 (shown as F0, F1, F2, . . . , F127, by way of example). Theframes are transmitted during a periodically occurring time spancorresponding to a transmission cycle which has a predetermined duration(e.g., 4 minutes), and which includes a predetermined number of frames(e.g., 128 frames). Each frame corresponds to a predetermined timeinterval (e.g., 1.875 seconds).

A frame includes an outbound sync 304, an optional selective calladdress 306, a message vector 308, and an outbound message 310. Theoutbound sync 304 is used by the selective call receivers 102 as a meansfor bit synchronization utilizing techniques well known in the art. Theselective call address 306 is used when selective call messages aretransmitted by the high power transmitter 104 to one or more addressedselective call receivers. When a message code is transmitted by the lowpower transmitter 108, selective call messaging is not required, becausethe message code is normally intended to be received by all selectivecall receivers 102 located within the transmission range of the lowpower transmitter 108. Under these circumstances, the selective calladdress 306 is not used.

The message vector 308 points to a time within the signaling format ofthe communication protocol 300 corresponding to the position of theoutbound message 310 intended to be intercepted by the selective callreceiver 102. The outbound message 310 comprises a selective callmessage 312 when the high power transmitter 104 is transmitting theoutbound message 310, or a message code 314 when the outbound message310 is transmitted by a low power transmitter 108.

FIG. 4 is an electrical block diagram of a selective call receiver 102that operates according to the present invention. The selective callreceiver 102 comprises a receiver antenna 402, a receiver 404, a powerswitch 406, a processor 408, a memory 412, user controls 414, analerting device 416, and an information interface 418. All the hardwareincluded in the selective call receiver may be conventional.

The receiver antenna 402 is a conventional antenna capable ofintercepting FSK signals transmitted from either the high powertransmitter 104, or one of the low power transmitters 108. The receiver404 is a conventional FSK receiver for receiving information during atleast one predetermined frame of the communication protocol 300, and fordecoding the received information to provide decoded information to theprocessor 408.

The processor 408 is a conventional processor such as, for example, anMC68HC11 manufactured by Motorola, Inc. The memory 412 coupled to theprocessor 408 is a conventional memory that includes, for example, aread-only memory (ROM), a random-access memory (RAM), and anelectrically erasable read-only memory (EEPROM). The ROM is used forstoring the programming information of the processor 408. Theprogramming information directs the processor 408 in controlling theoperation of the selective call receiver 102. The RAM is used, forexample, for message processing and for storage of selective callmessages. The EEPROM is used for storing at least one selective calladdress for identifying the selective call receiver 102, and for storingat least one canned message. As used herein, the term "canned message"means a message that has been previously stored in memory and isretained for future presentation upon demand.

The power switch 406 is a conventional switch controlled by theprocessor 408 for strobing the power sourced to the receiver 404,thereby providing a battery saving function.

The processor 408 is programmed to be responsive to decoded informationgenerated by the receiver 404. When the decoded information is a messagecode 314 received from a low power transmitter, the processor 408 isprogrammed to identify a corresponding canned message stored in theEEPROM of the memory 412. The selection of the canned message is based,at least in part, on the frame in which the message code 314 wasreceived. As described in greater detail below, this enables theselective call receiver 102 to select and present to its user a certaincanned message that is identified by virtue of the frame during whichthe message code 314 (or other information) was received. This alsoenables the selective call receiver 102 to determine its location, i.e.,which small coverage area 112 it is located in. In contrast, when thedecoded information is a selective call message 312 received from thehigh power transmitter (such as a typical personal message like "callhome"), the processor 408 is programmed to store the selective callmessage 312 in the RAM.

For both types of messages, the processor 408 is further programmed toalert the user of pending message(s) by way of the alerting device 416,which uses a conventional tactile or audible alerting mechanism. Oncethe user has been alerted, the user can invoke functions provided by theuser controls 414 to perceive the pending message(s). In response toinvoking the user controls 414, the processor 408 directs the pendingmessage(s) to the information interface 418. The information interface418 presents the pending message(s) to the user by way of a conventionalliquid crystal display (LCD), or alternatively a conventional audibledevice for playing out audible messages.

FIG. 5 is a diagram depicting exemplary frame assignments in acommunication system according to the present invention that does notemploy frame reuse, i.e., does not assign a particular frame to morethan one low power transmitter 108. In this example, the diagram showsfour small coverage areas 112, each of which is assigned one of theframes 0 through 3 (shown as F0, F1, F2, F3). A low power transmitter108 is located in each of the areas 112, as shown in FIG. 1. In thesmall coverage area 112 identified by F0, the low power transmitterlocated therein transmits message codes in frame 0. In the other smallcoverage areas 112, identified by F1, F2 and F3, the low powertransmitters located therein transmit message codes during frames 1, 2,and 3, respectively. Thus, in the arrangement shown in FIG. 5, all ofthe low power transmitters transmit during frames that are differentfrom each other and different from the frames used by the high powertransmitter 104.

A high power transmitter 104 is located in the wide coverage area 114,also as shown in FIG. 1. This high power transmitter is assigned theremainder of frames 4 through 127.

The low power transmitters 108 transmit message codes 314 (FIG. 3)during their assigned frames (F0 through F3), but during all otherframes the low power transmitters 108 are inhibited from transmittingmessage codes 314. Similarly, the high power transmitter 104 transmitsduring frames 4 through 127, and is inhibited from transmitting duringframes 0 through 3. Thus, in the arrangement shown in FIG. 5, eachtransmitter is assigned one or more frames that are mutually exclusivefrom the other transmitters. This frame assignment plan substantiallyprevents signal interference between adjacent transmitters in thecommunication system.

Frame assignments other than those depicted in FIG. 5 can also be used.For example, if the system operator wishes to allocate more transmissiontime to the low power transmitters, one way of accomplishing that is topermit each of the transmitters of FIG. 5 to transmit on a first uniqueframe, and then on each of the following fifth frames. Thus, thetransmitter in area 112 that is depicted as transmitting during frame 0(F0) can also transmit during every fifth frame thereafter, e.g., duringframes 5, 10, 15, etc. The transmitter assigned to frame 1 (F1) wouldtransmit during frames 1, 6, 11, etc. The high power transmitter wouldtransmit during frames 4, 9, 14, etc. The other low power transmittersfollow the same pattern. Other frame assignments can also be made,depending on the needs of the users of the system.

FIG. 6 is a diagram depicting frame assignments in a communicationsystem according to the present invention that employs frame reuse,i.e., that assigns the same frame to more than one transmitter. Thediagram includes four small coverage areas 112 identified as location 1,location 2, location 3 and location 4. These areas are assigned frames0, 0, 1, and 2 (shown as F0, F0, F1, F2). A low power transmitter 108 islocated in each of the areas 112, as shown in FIG. 1.

In location 1, the low power transmitter located therein transmitsmessage codes in frame 0. In locations 2, 3, and 4, the low powertransmitters located therein transmit message codes in frames 0, 1 and2, respectively. Thus, with the arrangement shown in FIG. 6, low powertransmitters that are mutually remote from each other (locations 1 and2) are allowed to transmit during a common frame (frame 0 in thisexample). The distance separating them assures a lack of significantinterference by transmitters operating during the same frame. However,transmitters that are adjacent to each other, and more likely tointerfere with each other, are preferably required to transmit duringdifferent frames. The wide coverage area 114 is assigned the remainderof frames 3 through 127.

As with the arrangement of FIG. 5, the low power transmitters used inFIG. 6 transmit message codes 314 only during their assigned frames.During all other frames, the low power transmitters 108 are inhibitedfrom transmitting message codes 314. Similarly, the high powertransmitter 104 transmits on frames 3 through 127, and is inhibited fromtransmitting on frames 0 through 2. This frame assignment plansuccessfully combines non-frame reuse and frame reuse plans withsubstantially minimal signal interference in the one-way communicationsystem.

FIG. 7 is a diagram depicting the preferred arrangement of cannedmessages in the memory 412 of the selective call receiver 102. Thecanned messages are conventionally preprogrammed in the EEPROM of thememory 412 by a service provider of the selective call receiver 102.Each group of canned messages is associated with the location of a smallcoverage area 112 corresponding to a low power transmitter 108. In thisexample, the first group of canned messages is associated with location1 in which a low power transmitter transmits during frame 0. The nextgroup of canned messages is associated with location 2, which isrelatively remote from location 1, and whose low power transmitter alsotransmits during frame 0. The other canned messages are similarlyassociated with locations 3 and 4.

The selective call receiver 102 selects one of its canned messages inthe following manner. Referring back to FIG. 7, it can be seen that aselective call receiver 102 stores canned messages 1 through 10 that areassociated with location 1 in FIG. 6. Each of the canned messages 1-10is selected and presented to the user in response to receiving a messagecode 1 through 10, respectively, during frame 0. Thus, if a selectivecall receiver 102 receives message code 10 during frame 0, cannedmessage 10 is selected and presented to the user of the selective callreceiver 102. Such a canned message may tell the user that "You are inlocation 1" or "The exhibits in location 1 will close in 10 minutes",for example.

If a selective call receiver receives message code 11 during frame 0, itwill select canned message 11 which may tell the user something relevantto location 2.

Similarly, receipt of a message code 1 through 10 during frame 1 causesthe selective call receiver 102 to select the corresponding cannedmessage among messages 21-30; and receipt of a message code 1 through 10during frame 2 causes the selective call receiver 102 to select thecorresponding canned message among messages 31-40.

It will be appreciated that an advantage of the present communicationsystem is that a selective call receiver can determine its locationbased, in whole or in part (depending on the extent of frame reuse) onthe frame in which it receives information. For example, when theselective call receiver 102 receives message code 5 in frame 0, theselective call receiver 102 knows that it is in location 1. When theselective call receiver 102 receives a message code in frame 1, theselective call receiver 102 knows that it is in location 3. Note thatdetermination of location does not require receipt of a message codewhen information is received during a frame that is unique to one of thelocations 112. Thus, a selective call receiver 102 that receives anyinformation during frame 2 will know that it must be in location 4.

It will be appreciated that locations assigned non-reuse frames canreuse message codes (as in the case of locations 3 and 4), whilelocations assigned reuse frames must be assigned unique message codes(as in the case of locations 1 and 2) in order for selective callreceivers 102 to be able to determine which small coverage area 112 theyare located in.

It will be further appreciated that in the case where message codes 314are accompanied by message information, the selective call receiver 102presents the message information to the user by way of the informationinterface 418. The message code 314 number informs the selective callreceiver 102 of its location, and that message information is appendedto the message code 314.

It will also be appreciated that the message code 314 is also used bythe selective call receiver 102 for identifying a canned message. Theselective call receiver 102 presents the canned message and messageinformation to the user by way of the information interface 418. Forinstance, the user might be told through the information interface 418,"News Flash! Exhibit 4 in location 1 is now open." The message "NewsFlash" is, for example, a canned message corresponding to the messagecode 314, while the message "Exhibit 4 in location 1 is now open" is,for example, the message information.

FIG. 8 is a flow chart 500 of the high power transmitter 104 operationaccording to the present invention. Instructions that correspond to thesteps shown in the flow chart 500 are programmed into the controller 206of the transmitter 104.

The flow chart 500 begins with step 502 where the high power transmitter104 receives synchronization signals from the time base 212 forsynchronizing the high power transmitter 104 to frames 302 included inthe periodically occurring transmission cycle of the communicationprotocol 300. In step 504, the high power transmitter 104 transmitsselective call messages 312 in at least a first predetermined timeinterval corresponding to at least a first frame assigned to the highpower transmitter 104. Using the example shown in FIG. 5, the high powertransmitter 104 transmits messages during frames F4 through F127,although it is not a requirement of this invention that the high powertransmitter 104 transmit during more than one frame.

In step 506, the high power transmitter 104 receives a message from acaller using the PSTN. The message is designated for transmission to oneof the selective call receivers 102 in the wide coverage area 114. Instep 508, the high power transmitter 104 waits for the arrival of anassigned frame 302 before transmitting the selective call message 312.When an assigned frame 302 arrives, the program proceeds to step 510where it transmits the selective call message 312 during at least thefirst assigned frame, while the low power transmitters 108 are inhibitedfrom transmitting during the same frame(s). Once the selective callmessage 312 has been transmitted, the high power transmitter 104 returnsto step 506 to process further messages received from callers. Thisprocess continues until all messages have been transmitted or until theallotted time for the assigned frames has elapsed.

FIG. 9 is a flow chart 600 of the low power transmitter 108 operationaccording to the present invention. Instructions that correspond to thesteps shown in the flow chart 600 are programmed into the controller ofeach low power transmitter 108.

Prior to operation in the field, the low power transmitter 108 isprogrammed by a service provider with message codes to be selectivelytransmitted in at least a second predetermined time intervalcorresponding to at least a second frame assigned to the low powertransmitter 108.

The flow chart 600 begins with step 604 where the low power transmitter108 receives synchronization signals from the time base 212 forsynchronizing the low power transmitter to frames 302 included in theperiodically occurring transmission cycle of the communication protocol300. In step 606, the low power transmitter 108 selects a message code314 from the group of message codes preprogrammed by the serviceprovider. The selected message code is designated for transmission toall selective call receivers 102 located within the transmission rangeof the low power transmitter 108. In step 608, the low power transmitter108 waits for an assigned frame 302 before transmitting the message code314. Using the example shown in FIG. 5, the low power transmitter 108waits for one of the frames 0, 1, 2 or 3, depending on which low powertransmitter 108 is preparing to transmit.

When an assigned frame 302 arrives, the low power transmitter 108proceeds to step 610 where it transmits the selective call message code314 during its assigned frame(s), while the high power transmitter 104is inhibited from transmitting during the same frame(s). Once themessage code 314 has been transmitted, the program proceeds to step 606to select further message codes for transmission.

FIG. 10 is a flow chart 700 showing how the selective call receiver 102is programmed to operate according to the present invention.Instructions that correspond to the steps shown in the flow chart 700are stored in the memory of the selective call receiver 102.

Prior to operation in the field, the selective call receiver 102 isprogrammed with groups of canned messages stored in the memory 412. Eachgroup of canned messages is associated with message codes and framescorresponding to the location of each low power transmitter 108 in thecommunication system. The selective call receiver 102 is furtherprogrammed to receive selective call messages 312 in at least a firstframe from the high power transmitter 104, and message codes 314 in atleast a second frame from a low power transmitter 108.

For example, the selective call receiver 102 may be programmed toreceive transmissions from the high power transmitter 104 during frames4 through 127, and to receive transmissions from a low power transmitter108 during frame 0 (assuming that the selective call receiver isexpected to remain in the small coverage area in which transmissions aremade during frame 0). If the selective call receiver 102 is expected tomove from one to another of all the small coverage areas 112, then itshould be programmed to receive transmissions during all the framesassigned to the low power transmitters 108 (i.e., frames 0, 1, 2 and 3).

The flow chart 700 begins with step 706 where the selective callreceiver 102 prepares to power up the receiver 404 during its assignedframes to receive selective call messages 312 and/or message codes 314,respectively. In step 708, the selective call receiver 102 waits for thearrival of an assigned frame. Assuming that one of the frames 4-127arrives, (assigned to the high power transmitter), the program proceedsto step 710 to process the message sent by the high power transmitter.When one of the frames 0-3 (assigned to the low power transmitters)arrives and a message code 314 is intercepted, the program proceeds tostep 712 where it selects a canned message corresponding to the assignedframe and message code 314 received.

Once the selective call message 312 and/or the message code 314 has beenprocessed, the selective call receiver 102 proceeds to step 714 where italerts the user, by way of the alerting device 416, of the pendingmessage(s) received. In step 716, the user reads the message by invokingfunctions provided by the user controls 414. The selective call receiver102 then returns to step 706 to prepare to receive further messages fromthe communication system.

The present invention provides a simple and low cost method for deliveryof messages by wireless local area networks located within a wirelesswide area network, with both networks operating on the same RF channel,and without the relatively long periods of latency sometimes experiencedwith prior systems. A selective call receiver operating within thecommunication network is able to determine which local area it islocated in on the basis of which frame and/or message code is used. Inaddition, the association of message codes with frames allows the reuseof frames among low power transmitters without relinquishing thecapability of the selective call receivers to identify the location ofthe low power transmitters.

What is claimed is:
 1. For use in a communication system having at leasta first transmitter transmitting information on a first frame and asecond transmitter transmitting information on a second frame of aperiodic transmission cycle, a selective call receiver,comprising:circuitry for receiving information including at least one ofa message code received during the first frame from the firsttransmitter and a same message code received during the second framefrom a second transmitter; a memory for storing a first and a secondcanned message, wherein the first canned message corresponds to themessage code being received in the first frame and the second cannedmessage corresponds to the same message code being received in thesecond frame; and a processor coupled to the memory and responsive tothe message code for identifying the first canned message in the memorycorresponding to the message code and the first frame, and identifyingthe second canned message in memory corresponding to the same messagecode and the second frame.
 2. A selective call receiver as set forth inclaim 1 wherein at least two transmitters that are remotely located fromeach other transmit during a common frame and transmit different messagecodes, wherein each stored canned message is associated with atransmitter and with a message code, and wherein the processoridentifies a stored canned message based on a received message code andon which frame the message code is received in.
 3. A selective callreceiver as set forth in claim 1 wherein the circuitry for receivinginformation including the message code decodes the received message codeand generates a decoded message code, and further wherein the processoris responsive to the decoded message code.
 4. For use in a communicationsystem having at least a first transmitter transmitting information on afirst frame and a second transmitter transmitting information on asecond frame of a periodic transmission cycle, a selective callreceiver, comprising:circuitry for receiving information including atleast one of a message code received during the first frame from thefirst transmitter and a same message code received during the secondframe from a second transmitter; a memory for storing a first and secondgroup of canned messages, wherein the first group of canned messagescorrespond to the message codes received in the first frame and thesecond group of canned messages corresponds to the same message codesreceived in the second frame; and a processor coupled to the memory andresponsive to the message code for identifying a first canned message ofthe first group of canned messages in the memory corresponding to themessage code and the first frame, and identifying a second cannedmessage of the second group of canned messages in memory correspondingto the same message code and the second frame.